Can previous graduates apply for China Unicom or China Mobile?

I am from Beijing China Unicom and can tell you about the situation in Beijing.

Under normal circumstances, China Unicom only recruits on campus. (Don’t mention the line operators to me~ They are not recruited by China Unicom at all. They are recruited by the third party "Taimei Company" in Beijing to provide them to China Unicom envoys.) But among our batch of campus recruiters, more than one of them has worked before. (but the time was short, only about two years), it is certain that they are all related.

The solid professional knowledge you mentioned... I personally think this is not particularly important...